[labnetwork] Oxford ICP helium backside cooling performance

[Luciani, Vincent (Fed)]

Hello All,

We have 2 Oxford Plasmalab 100 ICP etch tools that are heavily used.  100 mm wafers are the most popular.  I am sure I discussed with many of you the trials and tribulations about these tools.  My question is about a yur experiences and lessons learned with regard to keeping the helium leak rate from underneath the wafer under control.  I am trying to get a general idea of what is typical and how we are doing compared to that.  We have several users that utilize the cryonic etching capability of our tools so the helium cooling is very important.  For those using the tool at -100 C, we find that 8 sccm is too high and users request repair.  We generally try to keep the leak rate < 5 sccm at all time but find this difficult to do with the variety of substrates and etch recipes.  We made some progress by ordering  specially made quartz discs with a cutout for the wafer flat for better wafer positioning.  I am happy to share the dwg if anyone would like it.

What is your experience?  What leak rate do you find tolerable and at what leak rate do you shut the tool down.  Any tricks you can share?


Thanks,
Vince


Vincent K. Luciani
NanoFab Manager
Center for Nanoscale Science and Technology<http://www.cnst.nist.gov/>
National Institute of Standards and Technology
100 Bureau Drive, MS 6201
Gaithersburg, MD 20899-6200 USA
+1-301-975-2886





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